Radiation measurement tools are useful in a variety of applications, such as energy industry operations. Examples of energy industry operations include processes for evaluating subterranean formations such as natural gamma ray, induced gamma ray and density logging devices. For example, pulsed neutron porosity measurements involve bombarding a formation with high energy neutrons and monitoring the attenuation of the neutron flux by the formation at different distances from the neutron source. Pulsed neutron spectroscopy is based on the measurement of the spectrum of induced gamma rays emitted by the formation when it is irradiated by high energy neutrons.
Such tools utilize scintillation detectors to detect neutrons and gamma rays. A scintillation detector includes a scintillation material and a photodetector. An ionization particle (e.g., a neutron or a gamma ray emitted in response to neutron irradiation of a formation) interacts with the scintillation material and part of the energy released in the interaction reaction is converted into photons which travel inside of the scintillator until they reach the optical window of the photodetector. The photodetector converts the photons into an output electrical signal.
The accuracy of the measurement of the energy created in the interaction of ionization radiation with the scintillation material of the detector depends on how much light emitted from the scintillation event reaches the optical window of the photodetector. Challenges in taking accurate measurements may stem from impurities in a scintillation material or other components of a scintillation detector. For example, gamma ray scintillation detectors can have dimming issues due to partial opacity within the scintillator material dimming light flashes.